Police investigate a number of serious assaults

Police will be reviewing security footage to determine how two men were seriously injured in Joondalup.

The men, aged 20 and 22, were found with serious head injuries after an incident in the Joondalup CBD in the early hours of yesterday morning.

The younger of the men was found at a fast food shop while the older man made his way home before being taken to hospital.

He is currently in a coma while the younger man is being treated for skull fractures.

Detective senior constable Jamie Patterson says police are reviewing CCTV footage from the area, and want to speak to anyone with information.

"Something very serious has happened to these two men but we don't know yet whether it's an assault or a vehicle has been involved or both together, at the moment we've got very limited information from the public," he said.

And, a 47-year-old man remains in a critical condition in hospital after he was assaulted in a park in Yokine.

The man was found on Wordsworth Avenue with life-threatening injuries in the early hours of yesterday morning.

Forensic police spent yesterday scouring the area and speaking to people living nearby.

Police say an end-of-season football party was held at the park's clubhouse the night before but the victim did not attend.

Officers are investigating whether a group of men, believed to be in the park at the time, was involved in the assault.